Climate control systems may take different forms depending on the application. In a residential or commercial building, for example, typically a heating, ventilating and air conditioning (HVAC) system is used to heat and/or cool the air within the building. In automobiles, cooling may be provided by an engine-driven compressor, and heating may be provided by a heat exchanger that warms the passenger cabin with engine-warmed coolant. In either case, climate control may be provided by a controller that modulates the duty cycle of the cool air source and/or the warm air source. In some cases, the controller may also control the humidity in the conditioned space. The comfort perceived by an occupant of the conditioned space is typically a function of both an absolute temperature (e.g. a dry-bulb temperature) and the relative humidity.